US1268030A - Coating process. - Google Patents

Description

J.P.A.McCOY.

COATING PROCESS,

APPLICATION FILED JULY 3,1914.

1 ,268,030. Patented May 28,1918.

WHNESSES: INVENTOR IV 1 ,WV Z Ia/mg P/f I'M/:50)

WWW W/ ATTORNEY UNITED STATES PATENT OFFICE.

JAMES P. A. MCCOY, OF \KTILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTUBIN G COMPANY, A CORPORATION OF PENNSYLVANIA.

COATING PROCESS.

Specification of Letters Patent.

Patented May 28, 1918.

Application filed July 3, 1914. Serial No. 848,804.

To all whom it may concern:

Be it known that I, JAMFs P. A. MoCoY, a subject of the King of Great Britain, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Coatin Processes, of which the following is a specification.

My invention relates to processes of covering solid bodies with metallic or non-metallic coatings, and it has for its object to provide a coating rocess in which the coating material is de ivered upon the surface of the article to be coated in the form of a fine spray of molten material, the particles composing the spray being so small that the material solidifies instantl upon reaching the surface of the article tolie coated.

In the accompanying drawing, Figure 1 is a diagrammatic view illustrating one form of apparatus suitable for carrying out my process, and Fig. 2 is a longitudinal sectional view of a combined torch nozzle and delivery device adapted for use in another form of apparatus.

My invention may be considered as an extension of, and an improvement upon, the well-known Schoop metallizing process, according to one modification of which a bath of molten metal is disintegrated by a rapid current of compressed and heated gas, the resulting spray bein delivered by the current of gas to the col d surface of the article to be coated. According to another modification of the Schoop process, a wire of the metal to be used as the coating is fed into the flame of an oxyhydrogen or oxyacetylene torch, which melts the end of the wire and projects the resulting spray of molten metal against the article to be coated, as in the first modification of the process.

According to my improved process, I am not restricted to the use of metal as the coating material, but I nay coat solid objects with either metallic or non-metallic substances. If the coating is to be metallic, I proceed by feeding an oxid of the coating metal, in finely divided form, and at a definite rate, depending upon the nature of the oxid and the thickness of the desired coating,

into the flame of an oxyhydrogen or oxyacetylene torch which is directed toward the body to be coated. The oxids are reduced to a liquid metallic condition in the reducing flame of the torch, and are blown against the object to be coated as in the Schoop process. Other readily-reducible metallic compounds may be substituted for the oxids.

If a non-metallic material, such as silica or alumina, is to be used as the coating material, it is fed into the flame of the torch in a finely divided condition, as in the case of the metallic oxids. Here, however, there is no chemical transformation of the coating substance, but it is merely melted, and the spray of molten material is directed against the object to be coated as in the other methods described.

In order to intensify the heat, and provide a larger melting and reducing area into which the coating powder is introduced, a torch having several united streams of oxygen and acetylene, hydrogen, or other combustible gas may be employed.

Even the most fragile and combustible materials, such as cloth, paper and lace, may be coated with molten material by my process, since the individual particles which compose the molten spray are cooled and solidified so rapidly, upon reaching the article that is being coated, that the article is not burned or otherwise injuriously affected.

One valuable application of my invention is the coating of metallic resistance elements and other electric apparatus with insulating coatings of silica, alumina, or other highly refractory insulating material. In this case, and in any other case where a metallic body, that is subsequently to be heated, is coated with silica or other non-metallic brittle substance, the metal should be heated before being coated in the manner described above. This is necessary because, if the metal is coated when cold and afterward heated, its expansion will break the brittle refractory coating.

The finely divided coating material may be fed into the flame of the torch in any convenient manner. As shown in Fig. 1 of the accompanying drawing, the powdered material is placed in a hopper 1, that communicates with a worm conveyer-2, the delivery end 3 of which is disposed directly above the flame 41 of an oxyacetylene, oxyhydrogen or other form of torch 5 that is directed toward the object 6 to be coated. As shown in the drawing, the object 6 is a continuous web or filament of flexible material that is unwound from a roll 7 and passes across the path of the flame 4 and around a guide roller 8, the coated web being rewound on a roller 9.

Instead of dropping the powdered coating material transversely into the flame, as in the apparatus shown in Fig. 1, the material may be fed through a passage that is centrally disposed within the nozzle of the torch. A nozzle provided with such a passage for feeding the coating material, is illustrated in Fig. 2, wherein a nozzle 10 is shown provided with a plurality of annular ports 11 and 12 through which oxygen and hydrogen acetylene, or other combustible gas, may e fed into the combustion chamber 13 at the outer extremity of the torch. A central passage 14: is disposed within and inclosed by the walls of the ports 1] and 12. It will be evident that powdered material, fed through the passage 14 in any convenient manner, will be received in the highly heated combustion chamber 13, and, if the coatin material is a metallic oxid, it will be reduce to metal therein. A torch having several nozzles 10 may be employed, the nozzles being so disposed that their flames are united, thus forming a large heating and reducing field. When such an arrangement is adopted, only a single material-feeding passage 14 is required, and this passage is preferably disposed symmetrically with respect to the nozzles of the torch. Thus, one of the series of nozzles may be constructed, as shown in v Fig. 2, with the passage 14: therein, and the remaining nozzles of the torch may be constructed without the passage 14:.

It is to be understood that the apparatus shown is merely illustrative, and that any other convenient means may be employed for feeding a definite amount of the powdered coating material into the flame 'of the torch. It will also be obvious that the object to be coated is not necessarily presented to the spray of metal in the form of a continuous web or filament, since any desired solid article may be coated according to my process.

Any metallic oxids that are capable of being reduced to metal in a flame of high temperature may be employed in my process,

and all non-metallic substances are likewise suitable for my use that can be melted without combustion in such a flame. My process may, therefore, be carried out with a wide variety of non-metallic substances and with nearly all metallic oxids. In view of the wide range of conditions under which my on my invention except such as are indicated in the appended claims.

I claim as my invention:

1. A coating process that comprises reducing and liquefying a powdered material consisting of a metallic compound and projecting the liquid against the surface to be coated.

2. A coating process that comprises reducing and liquefying a powdered material consisting of a metallic oxid and projecting the liquid against the surface to be coated.

3. A coating process that comprises reducing a powdered material consisting of a metallic compound to molten metal and simultaneously projecting the reduced metal against the surface to be coated.

4. A coating process that comprises reducing a powdered material consisting of a metallic oxid to molten metal and simultaneously projecting the reduced metal against the surface to be coated.

5. A coating process that comprises reducing a powdered material consisting of a metallic compound to molten metal and simultaneously projecting the reduced metal in the form of a spray against the surface to be coated.

6. A coating process that comprises reducing a powdered material consisting of a metallic oxid to molten metal and simultaneously projecting the reduced metal in the form of ,a spray upon the surface to be coated.

7. A coating process that comprises reducing a finely-divided metallic compound to molten metal and simultaneously projecting the reduced metal against the surface to be coated.

8. A coating process that comprises re ducing a finely-divided metallic oxid to molten metal and simultaneously projecting the reduced metal against the surface to be coated.

9. A coating process that comprises introducing a powdered material consisting of a metallic compound into a flame that is directed toward the surface to be coated, whereby the said compound is reduced to metal and projected in a spray against the said surface.

10. A coating process that comprises introducing a powdered material consisting of a metallic oxid into a flame that is directed toward the surface to be coated, whereby the said oXid is reduced to metal and simultaneously projected in a spray upon the said object.

11. A coating process that comprises introducing a finely-divided metallic compound into a reducing flame thatis directed is reduced to molten metal which is pro- 10 toward the surface to be coated, whereby the jected in a spray upon the said surface. said compound is reduced to molten metal In testimony whereof I have hereunto subwhifch is projected in a spray upon the said scribed my name this 30th day of June, 1914.

5 en ace.

12.- A coating process that comprises in- JAMES MCCOY troducing a finely-divided metallic oxid into Witnesses: a. reducing flame that is directed toward the W. H. KEMI'DON, surface to be coated, whereby the said oxid B. B. Hnms,

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